This is a bit of an awkward/uncommon translation. In Chinese, 加油 is often used as words of encouragement, equivalent to "Good luck!". The current translation "Come on!" is applicable to sports but is unlikely to be used in conversation. Students here are more likely to come across 加油 meaning "Good luck".
This should not even be included. 加油is such a commonly used phrase and used for a million different settings that are just hilarious to think about as a native English speaker. It's impossible without context to have the correct answer. Even with context there's a dozen possivle correct answers.